Torch them out? 3406 B exhaust manifold bolts

[Wilmath]

I am working in a Cat 3406B trying to get the last two exhaust manifold studs out. One one of them
we got an easy out stuck so we tried burning it out. We ended up grinding it out but the original 1/4 inch hole
I drilled down the center has become enlarged and I can just start to see threads on the upper part.

Since this hole is boogered up and has also been heated can I just torch out the remainder of the stud?
Thanks
Rick

 

[Delmer]

yeah, you might be able to. I'd try it a couple times just heating the remains of the broken stud till they start to spark, then let it cool completely, try another easy out, GENTLY. The heat should shrink the confined metal and let it turn out once it's cooled.

The best way to get a broke bolt out is to weld a nut to the top, let it cool, then work it ever so slightly until it is loose then keep working it a little more. It's the heat and cooling that does the job, the nut is just there for convenience.

 

[kshansen]

The best way to get a broke bolt out is to weld a nut to the top, let it cool, then work it ever so slightly until it is loose then keep working it a little more. It's the heat and cooling that does the job, the nut is just there for convenience.

Agree the weld the nut works about 95% of the time. Only time I was not able to get a couple studs out was a 3408 that was run most of the season with a couple broken exhaust studs on right bank. All I can figure is the carbon worked it's way in and down the stud to lock it tight.

Even had the "expert" from Cat dealer give it a go and he tried three times on those buggers before he got out the special jig with the bushings to center the drill and drilled them out with I believe a special cobalt drill bit.

 

[Nige]

Try melting some candle wax into the threads. That will often loosen a stuck stud.

 

[Old Doug]

Try melting some candle wax into the threads. That will often loosen a stuck stud.

I have tryed this several times and it didnt seem to help. On a ford truck very back bolt on the hard drivers side i welded on it over 12 times to get it out. Weld a glob hit it weld another glob flaten it and keep going tell you have a glob to get vise gripes on then work it back and forth.

 

[RZucker]

I have taken a lot of these studs out using the welding trick, some times it takes 4-5 tries. If the stud has broken just below the surface I will use a tiny die grinder burr to take out the top thread of the casting to clear the pulled thread on the stud, that helps quite a bit because that top thread on the stud is jammed into the head. I will also use that burr to get me an accurate center in the stud so a drill bit wont wander off center. Next I drill a 3/16" hole (no bigger) in the stud 'til I get to the bottom of the stud (not the water jacket), I use a left hand cobalt bit. Now at that point just for grins I'll spray some PB Blaster in the hole to get some in behind the stud threads and then try an extractor (gently). If it wont move then I heat the stud and let it cool and try again (gently).
The next trick is to fill the hole in the stud with .023 welding wire and weld the nut on. Usually that gets it out. I have had to redrill and use a threaded sleeve a time or two.
A couple years ago I was changing manifold gaskets on a D9N and didn't have a single stud break, but when I unscrewed the RH rear stud it started spraying me with coolant. Somebody drilled a little deep.

 

[Truck Shop]

If you can see threads on one side the hole must be off center. In this case sharpen a punch to a point, use the punch point on the thickest side of whats left of the threads to cave the rest in on it's self.
And grab it with needle nose pliers. I have done this many times to remove off center threads. It's going to need a Heli-Coil anyway at this point. Once it's collapsed spray with penetrating oil to help spin
it out. Removing broken studs is one of my specialties. The bad ones on a B or 5EK is the thermostat housing bolts.

 

[RZucker]

More than once I have gone after those thermostat housings with a cutoff wheel on a grinder. Once the bolt head breaks off, all bets are off. Sometimes "destruction is the better part of valor".

 

[fast_st]

I've had great luck with the weld-a-nut technique. Often with exhaust bolts, I'll try the spin but if its going to break, cut the head off and remove the part. rappy tap tap on the remaining stud to see if it'll loosen, sometimes just removing the tension works well. Otherwise you can drill a hole about 30% of the diameter of the stud to the bottom, either a welding tip down the middle or a mig wire feed down the middle. Once it cools from red hot it'll shrink a few thou and might just loosen up.

 

[Truck Shop]

More than once I have gone after those thermostat housings with a cutoff wheel on a grinder. Once the bolt head breaks off, all bets are off. Sometimes "destruction is the better part of valor".

Gayle the other in the shop had thermostats to change on 3406 6TS on a Sunday morning during harvest. He couldn't get the bolts to move totally corroded on two of them. I traded jobs with him.
I used a cut off wheel and removed the bolt heads then free hand drilled the front section bolts removed the front then continued drilling the rear section bolts. I handed him four pieces roughly
2 1/4 long 3/8 bolts drilled end to end dead center 5/16 id. After that he would just hand me the drill and walk away.

 

[Wilmath]

I finally got them off and am now trying to reassemble everything.
Does anybody know how much I torque the studs and also the lock nuts? Does it matter which side of the gaskets are applied to the manifold?
Thanks everyone for the responses

 

[kshansen]

The standard torque for a 3/8-16 taper lock stud is 20 +/- 3 lb/ft.

Did not see a s/n above, might have missed it but below is the torque sequence for the exhaust manifold. Does not mention which way the gaskets go.



One more thing! Is this a one piece manifold or three piece? I looked at some newer versions of the 3406 (3406 E) and they have three piece manifolds and do use a different torque sequence. And they also show a higher torque on the studs of 26+/- 4 lb/ft.

 

[Wilmath]

The manifold came off in one piece but looks like it is in 3 sections. The sections don't move around.
Do you know the bolt sequence of the 3 piece manifolds?

 

[kshansen]

A Little more searching and all the 3406 B's show the same pattern it's when they went to 3406C that they changed the pattern:
See that one below:


Along with a slight change to the torque range.

Not sure what anyone else would say but I kind of like the pattern for the "C" a little better than the "B"!

 

[Nige]

A suggestion. If the manifold is in 3 pieces you would be well advised to separate them (it will probably require plentiful application of heat) and then buff the Bejasus out of the joints with a flap wheel so that they slide well in and out of one another. If you can see daylight through the joints so much the better. Then when you install the manifolds and tighten up the nuts on the studs nothing will need to be twisted out of shape and pulled to within an inch of its life to get the manifolds tight up against the cylinder head. The joints will seize up again over time but by then anything that needed to move to get the alignment right will have moved long before.

 

[kshansen]

Guess I missed that point!

 

[Tenwheeler]

The best way to remove them depends on your skills, tools and abilities. Glade your got yours out and there is a lot of good info listed. I did it this way today. Did not have to pull the thermostat housing to drill holes this way. Also used a torch, hammer and punch.